There is something wrong with OSX Java 1.7 2D performance

While doing performance optimizations to my small Thrust-style game project grambers I noticed something really weird: when I upgraded the JavaVM from 1.6.0_31 to 1.7.0_04-b21 the frames-per-second halved.

As grambers is scala based project I first suspected that the problem is related to java-scala version incompatibility. I pretty quickly ruled it out by measuring where the extra time was spent: in Java's graphics2D.drawImage. I then tested the Java2D official example DukeAnim by just adding a measurement around the paint.drawImage call and got the following results on my MacBook Pro:

reynders$ java -version 
java version "1.6.0_31" Java(TM) SE Runtime Environment (build 1.6.0_31-b04-415-11M3635) Java HotSpot(TM) 64-Bit Server VM (build 20.6-b01-415, mixed mode) reynders$ java DukeAnim 
50 draws took 19ms
50 draws took 23ms
50 draws took 24ms
50 draws took 29ms


reynders$ java -version 
java version "1.7.0_04" Java(TM) SE Runtime Environment (build 1.7.0_04-b21) Java HotSpot(TM) 64-Bit Server VM (build 23.0-b21, mixed mode) 
reynders$ java DukeAnim 
50 draws took 226ms
50 draws took 219ms 
50 draws took 222ms 
50 draws took 217ms 

10x reduction in speed! I ran the same tests on a ages old Lenovo T60p using Java 1.7.0_04:

java -version 
java version "1.7.0_04" Java(TM) SE Runtime Environment (build 1.7.0_04-b20) Java HotSpot(TM) Server VM (build 23.0-b21, mixed mode) 
java DukeAnim 
50 draws took 23ms 
50 draws took 33ms 
50 draws took 25ms 
50 draws took 27ms 

So the problem seems to be in the Java 1.7 OSX implementation. As of writing oracle does not accept OSX bug reports in their java bugzilla and the macports site is down I decided to create this blog post as a way to help people with the same problem. I will report a bug to Oracle when possible - if the problem does not go a way before that :)

A dragonfly on a rock in Khao Sok Rainforest, Thailand